On the Level

Prioritising staff safety, a US cement works installed a level scanner to monitor bin levels in its clinker storage silo. This eliminated the need to manually measure the height of the material in the silo and thus minimised the risk of staff injury. The chosen 3D level scanner is particularly suited to the dusty and challenging environment.

To check the clinker level in a ø21 x 35m (ø70ft x 115ft) silo at a large cement works in the USA, plant staff would previously be required to climb a straight ladder or use a man lift, which could not be operated when winds exceeded 15mph. Once on the roof, manual measurements were taken at five different hand tape measurement ports at various locations across the silo. Due to the uneven surface of the clinker stored in the silo, a single measurement point did not provide adequate level information for this wide, tall structure.

Improving on accuracy and worker safety

To improve the safety of staff as well as the accuracy of level measurement, the works decided to install a level scanner, thus eliminating the need to climb the bin to get measurements that were not entirely accurate. As a result, a BinMaster 3DLevelScanner was installed in an existing portal on the silo roof. The BinMaster technical services manager worked with the customer to adapt the mounting of the 20cm (8in) scanner mounting flange to the existing 27.5cm (11in) opening. The opening had been home to an older open air radar device that had never worked properly, making the customer rely on taped measurements for level information until the installation of the 3DLevelScanner was complete.

The customer also installed a remote communications device that provides a remote link with BinMaster’s engineering laboratory during the initial installation period, allowing bin parameters to be loaded in the software and fine-tuned for optimum performance.

Due to the uneven material surface in the clinker silo, the customer selected the 3DLevelScanner’s MV model, which includes a feature that creates a graphical visualisation of the topography in the bin. 

In addition to the mapping, the 3DLevelScanner also provides a wealth of information such as minimum, maximum and average distances to material which can be helpful in detecting silo conditions such as sidewall build-up or bridging, or cone up or cone down. 

Facing a challenging operating environment

Cement plants provide many challenges in terms of materials management and storage. The materials used in cement production are varied and as such, have different characteristics. While some such as clinker are heavy, abrasive, coarse and lumpy, others are powdery, dusty, sticky and clumpy. For these materials, the acoustics-based technology used by the 3DLevelScanner is particularly suited to help improve operational efficiency. 

In the case of the US cement plant, there were several reasons to select this type of scanner: 

Multiple-point measurement for improved accuracy
By measuring and mapping the material surface at multiple points and providing minimum, maximum and average distances the 3DLevelScanner calculates a volume estimate that is more accurate than radar or ultrasonic devices. 

The 3DLevelScanner employs an acoustics-based technology, therefore no equipment comes into contact with the surface of the material. This eliminates the risk of equipment breaking or becoming trapped in material and potentially causing damage to sweepers or conveyors in the bottom of the silo.

Penetrates dust
The dusty environment in the cement industry makes it difficult or impossible to provide accurate readings using radar or ultrasonic technologies. The 3DLevelScanner penetrates dust and provides a highly accurate volume measurement, even in extreme conditions.

Detects sidewall build-up
By taking multiple measurements within the bin and then mapping the topography in the bin, the computerised profile created by the 3DLevelScanner can show where material has built up on the sides of the silo. By detecting irregularities in the material surface, excessive build-up can be accounted for in volume calculations. If a single point device on a tape measure were dropped, depending on where the measurement was taken, it might show the bin is almost empty, even when a significant amount of material remains in the bin. 

Excels at measuring powders
Many materials used in the production of cement are powders such as fly ash that are prone to creating dust, bridging or building up on the sidewalls of the silo. The surface of powdery materials tends to be irregular, which makes the 3DLevelScanner’s multiple-point measurement and mapping capability particularly suited for the challenges associated with powders.  

Challenging materials
Hard-to-measure materials, such as clinker, are stored in silos where there is a requirement to measure the quantities quite accurately. With its highly accurate volume estimates, the 3DLevelScanner offers an alternative to weighing the material.

The 3DLevelScanner automatically cleans itself, which reduces the frequency of preventive maintenance. Suspended dust tends to stick to radar or ultrasonic devices, requiring cleaning or maintenance at frequent intervals for the instrument to continue working. The 3DLevelScanner’s proven self-cleaning technology effectively prevents dust from adhering to the transducers.

International Cement Review
Prioritising staff safety, a US cement works installed a level scanner to monitor bin levels in its clinker storage silo. This eliminated the need to manually measure the height of the material in the silo and thus minimised the risk of staff injury. The chosen 3D level scanner is particularly suited to the dusty and challenging environment.

Preventive maintenance alerts
By detecting sidewall build-up early, silos can be cleaned and serviced before material hardens and becomes even tougher to remove from the 
silo. Preventive maintenance can be performed early when it is an easier and less expensive undertaking.

Prevent silo collapse
Excessive build-up on one side of a silo can cause a silo to collapse. By detecting the build-up of material early, the situation can be corrected and excessive damage to the silo and surrounding structures can be avoided. Installing a 3DLevelScanner can lead to a reduction of insurance claims and costly, time-consuming rebuilding of structures. 

Accommodating storage diversity

This large cement production facility has many silos of various sizes from very tall, large and wide, to narrower, cone-bottomed silos used for load-out. Some materials are stored and staged in bunkers, piles or open bins where a volume estimate may be needed for inventory purposes. To accommodate such varying structures, 3DLevelScanners come in a range of models that are suited to different types of vessels.

Very tall silos – the M and MV models can provide a very high level of volume accuracy in bins up to 13.7m (45ft) wide and 60m (200ft) tall.

Narrow silos – In narrow-diameter silos, an S model measures in a narrower beam angle or an RL model can be used cost-effectively to monitor levels in a highly-dusty environment. The plant can optimise the manufacturing process by starting to fill according to a ‘minimum level’ reading and stop the fill according to a ‘maximum level’ reading. Automated alerts in the software simplify the monitoring process for plant personnel.

Extremely wide silos – For silos up to 27.4m (90ft) wide, the MVL model integrates two or more 3DLevelScanners with highly-specialised software that combines the data from the multiple scanners into a very accurate volume estimate. A 3D graphic shows where high and low spots are and helps manage filling and emptying points.

Bunkers, open bins and piles – A 3DLevelScanner can measure and map the surface area of the material inside a bunker, open bin or pit and provide a volume estimate of the contents.

Small silos – With its 30˚ beam angle, the S model is ideal for smaller silos. When a very high level of accuracy is desired – such as when processing powdered materials – the M or MV models can be used.

MultiVision software – When there are multiple 3DLevelScanners installed on site, MultiVision software can be used to view the status of all silos on a single screen, eliminating the need to review each silo individually. The material contained in each silo and the silo can be labelled for its location on site. One person can monitor and manage all silos, and receive alerts when levels are getting too high or when a silo needs replenishment. This enables the cement plant to effectively gauge and manage silo levels. 

The tough material challenge

The 3DLevelScanner accurate-ly measures the level of tough materials, including:
• calcium
• chalk
• clay
• clay slate
• crushed shells
• fly ash
• gravel
• grit
• gypsum
• iron ore
• lime
• limestone
• marl
• sand
• shale
• silica
• silica sand
• slag
• slate